This is not really a fair assessment. The most cost effective treatments can be self administered. But if you are coming in to see me because of persistent knee pain, more often that not you have already tried tylenol and over the counter nsaids (ibuprofen, etc.), and your pain has been persistent. The next set of treatment options, aside from maybe some physical therapy, are more expensive, because they involve using drugs that are more expensive or treatment measures that are more expensive. With re: PRP, it is not covered by insurance, since the benefits of it over a placebo are still not entirely clear. Many doctors offer it however, and to insure accuracy of needle placement, they usually perform it under ultrasound guidance- not something most people would be able to do on their own, at least not yet. As more and more physicians offer it, and if it remains uncovered, market forces will drive the prices down (like Lasik), although I'm doubtful PRP is considered an effective treatment option in the future.
I don't disagree with the notion that healthcare remains quite expensive in general. I see telemedicine, for certain conditions, reducing costs and maybe Direct Primary Care - bundling care into one package instead of serving it piecemeal could be a good way to go forward.